Process for forming a casting with a sliding surface by high pressure casting

ABSTRACT

A process for forming a sliding surface of a casting by a high pressure casting operation in which particles of any material suitable for improving the lubricating property, wear resisting property or the like of the sliding surface are adhered, in the form of a layer, by a binding agent of synthetic resin to a surface of a casting mold that is to form the sliding surface of the cast product. The casting material is supplied under high pressure into the casting mold to effect casting and to transfer the particles from the mold to the cast product. The resin binding agent is burned by the casting material and serves as a release agent.

United States Patent 1 Ikeda et al.

[4 1 July 10, 1973 [54] PROCESS FOR FORMING A CASTING WITH A SLIDING SURFACE BY HIGH PRESSURE CASTING [75] Inventors: Kazunori Ikeda, Tsurugajima;

Takeo Arai, Tokyo;

Kiyohisa Iwata; Tsuneo Kishida, both of Suzuka; Takuo Yamamura, Saitama; Taichiro Kayama, Yamato, all of Japan [73] Assignee: Honda Giken Kogyo Kabushiki Kaisha, Tokyo, Japan [22] Filed: Oct. 4, 1971 [21] Appl. No.: 186,352

[30] Foreign Application. Priority Data Oct. 3, 1970 Japan .Z 45/8637970 [52] US. Cl. 164/97 [51] Int. Cl B22d 19/08 [58] Field Of Search 164/97 [56] 0 References Cited UNITED STATES PATENTS 1,072,026 9/1913 Morris 164/97 2,260,593 10/1941 Wittlinger et al 164/97 FOREIGN PATENTS OR APPLICATIONS 1,949,777 l/1970 Germany 164/97 Primary Examiner-Robert D. Baldwin Att0rneyEric H. Waters et al.

[57] ABSTRACT A process for forming a sliding surface of a casting by a high pressure casting operation in which particles of any material suitable for improving the lubricating property, wear resisting property or the like of the sliding surface are adhered, in .the form of a layer, by a binding agent of synthetic resin to a surface of a casting mold that is to form the sliding surface of the'cast product. The casting material is supplied under high pressure into the casting mold to effect casting and to transfer the particles from the mold to the cast product The resin binding agent is burned by the casting material and serves as a release agent.

9 Claims, 3 Drawing Figures PATENIEU JUL 1 men WV 1 M PROCESS FOR FORMING A CASTING WITH A SLIDING SURFACE BY HIGH PRESSURE CASTING SUMMARY OF THE INVENTION tion of a mold to form the sliding surfaceportion of a cast product, and the material to be cast is supplied under high pressure into the mold.

It has been attempted to use an aluminum alloy for producing the cylinders of an internal combustion engine, but cylinders of this kind are poor in lubricating property and have a strong tendency to cause such dis- LII 2 the surface thereof which comes in" contact with the core metallic mold 6. It is essential to this invention that the casting be a high-pressure casting such as die casting. If the casting is an ordinary shell mold or metallic mold casting, when molten metal has entered the casting mold, the binding agent is decomposed by the heatto generate gas and there takes place a so-called blowing" and a firm attachment of the particles with the casting product cannot be obtained. If, however, the casting is a high pressure casting such as die casting, the molten metal fills the casting mold instantly and penetrates, owing to its high pressure, among the particles combined together by the binding agent so that the particles are transferred to the metal, and the molten metal is then solidified rapidly, and accordingly there is not caused blowing by the thermal decomposed gas. Thus, the binding agent layer 7 is firmly embedded advantages as biting, seizing, etc. in thecourse of slid- BRIED DESCRIPTION OF THE DRAWING F IG. 1 is a fragmental sectional side view of a cylin- 'der having a sliding surface according to this invention;

FIG. 2 is a sectional side view of a die casting apparatus for casting the product of FIG. 1; and

FIG. 3 is a enlarged sectional side view of a portion of the core metallic mold of the apparatus.

DETAILED DESCRIPTION Referring to the accompanying drawing therein is shown in FIG. 1 a lubricating and/or wear-resisting layer 2 formed on the inner peripheral surface of a cylinder I. In order to form layer 2, a metallic core mold 6 is arranged in a casting mold 3 comprisinga stationary metallic mold 4 and a movable metallic mold 5 of a die casting apparatus, and particles 8 of graphite, iron, molybdenum or the like are adhered tothe outer surface of core mold 6 by a layer of binding agent 7 chiefly composed of synthetic resin so that a layer of the particles is formed thereon. The binding agent may be, for example, a thermosetting resin such as a phenol resin, an epoxy resin or the like dissolved in a solvent such as alcohol or the like, and the binding agent is applied to the outer surface of the core mold 6 by means of soaking, painting, spraying or the like, whereafter the particles 8 are adhered thereto. The particles 8 are 0.3 to 1.5 mms in size, and the binding agent layer 7 having the particles 8 adhered thereto is then heated to, for example, about 200 C for curing thereof.

After the core mold 6 thus prepared isplaced in the casting mold 3, molten aluminum alloy is injected under high pressure into the mold 3 through a runner 9, whereupon the casting product 1 as shown in FIG. 1 is obtained in which the particles 8 are embedded in which casting is effected. But in this process, the

sprayed metal particles are fused and combined together to form a metal layer, so that the metal layer is cast in the casting metal. This process has the disadvan tage that the core mold is limited to use of a breakable material such as a sand mold so as to be removable after the casting operation, so that the same is not suitable fora casting operation requiring accuracy in size such as die casting.

In this-invention, the core mold and the particles are combined together through the binding agent and this binding agent is burned, so that the binding agent serves as a mold releasing agent and the core can be easily removed. Additionally, since the particles are combined with the core through the binding agent, the particles may be metallic or non-metallic.

Forimproving the wear resisting property, there are used metallic particles such as molybdenum, cobalt,

iron, manganese, silicon etc.; metallic oxide particles such as aluminum oxide, zirconium oxide etc.; nitride particles such as boron nitride etc.; and carbide particles such as silicon carbide etc. For improving the lubricating property, there can be used graphite, mica, steatite, molybdenum dioxide, lead, bismuth, lead sulfide, lead oxide, tin oxide, and fluorite.

Thus, according to this invention, particles of any desired material excellent in lubricating property or wear resisting property or the'like are adhered in the form of a layer through a binding agent of synthetic resin to such a portion of a casting mold that is to form a sliding surface of a cast product, and the particle layer is then firmly combined with'the metal surface of the casting by high pressure casting, whereby the casting product can be easily provided with a sliding surface having excellent lubricating property, and/or wear resisting property or the like. Additionally, since synthetic resin is used as the binding agent, any desired particles, regardless of whether metallic or non-metallic, can be used for forming the particle layer, and the binding agent is burned to serve as a mold releasing agent for facilitating the mold releasing operation. Thus, an excellent casting process for forming a sliding surface having lubricating property and/or wear resisting property or the like can be provided.

What is claimed is:

l. A process for forming a cast surface which is to be slidable with respect to another surface, said process comprising providing a casting mold having a surface against which the casting material is to come into contact to form said cast surface, adhering particles onto the surface of the casting mold by a binding agent of synthetic resin and effecting die casting by injecting the casting material under pressure into the mold (a) to transfer said particles from the surface of the casting mold onto the cast surface and (b) to burn said binding agent and cause the latter to remain as a release agent enabling separation of the cast product from the mold.

2. A process as claimed in claim 1 wherein said particles have lubricating property.

3. A process as claimed in claim 2 wherein said particles are graphite, stealite, mica, molybdenum dioxide, lead, bismuth, lead sulfide, lead oxide, tin oxide or fluorite. 1

4. A process as claimed in claim 1 wherein said particles have wear resistant properties.

5. A process as claimed in claim 4 wherein said particles are a metal, a metal oxide, a metal nitride or a metal carbide.

6A process as claimed in claim 1 wherein said particles are metallic.

7. A process as claimed in claim 1 wherein said particles are non-metallic.

8. A process as claimed in claim 1 wherein said binding agent is an epoxy or phenol resin.

9. A process as claimed in claim 1 wherein said particles are formed of a size between 0.3 and 1.5 mm. 

2. A process as claimed in claim 1 wherein said particles have lubricating property.
 3. A process as claimed in claim 2 wherein said particles are graphite, stealite, mica, molybdenum dioxide, lead, bismuth, lead sulfide, lead oxide, tin oxide or fluorite.
 4. A process as claimed in claim 1 wherein said particles have wear resistant properties.
 5. A process as claimed in claim 4 wherein said particles are a metal, a metal oxide, a metal nitride or a metal carbide.
 6. A process as claimed in claim 1 wherein said particles are metallic.
 7. A process as claimed in claim 1 wherein said particles are non-metallic.
 8. A process as claimed in claim 1 wherein said binding agent is an epoxy or phenol resin.
 9. A process as claimed in claim 1 wherein said particles are formed of a size between 0.3 and 1.5 mm. 